Q. Why should we consider your limited sample size “study” to be anything more than anecdotal? How do you justify it as “science” and not simply “story telling”? –Matti

A. As Dubner and Levitt of Freakonomics did in their fabulous book, my accounts of my “do(n’t) try this at home” parenting interventions—bribing my kids to do math, not teaching them to decode words on the page, exposing them to sewage to build up their immune systems and so forth—are meant to be a way in to talk about the existing research that is based on large samples, randomized controlled trials and cutting-edge econometric analysis. But would you rather read pages about whether or not the exclusion restriction is violated in a particular instrumental variable model of divorce? Or relegate that to endnotes so that you can hear about how my crazy family lived—like the Isaac Bashevis Singer tale—with a house full of animals to prevent childhood allergies? Ok, maybe don’t answer that.

Q. Day care vs. home mom: which kids test better? –Caleb B

A. My reading of the “mommy wars” literature is that the secret variable that resolves many of the contradictory studies is social class. Namely, rather than it being good or bad per se for a mother to stay home with her young children, the effect seemed to depend on the socioeconomic status of the mother herself. The more time that highly educated mothers were with their kids—as opposed to sending them to day care—the better those children did on cognitive tests. But for less educated mothers, kids did better when they went off to preschool and other structured activities. Hence the big effects of Head Start and other such programs prepping low-income toddlers for K–12 schooling. But also the negative effects in Canada, for example, when universal pre-school was instituted.

This makes sense: If you are a highly educated parent, who is better for your kid to learn from than you? But if you are disadvantaged educationally, then why not expose your child to caregivers who may have more human capital that you do? (Of course, in terms of opportunity costs of forsaken wages, the logic goes the other way.) A classic (if somewhat flawed)[1], study by psychologists Betty Hart and Todd Risley conducted the simple task of counting how many words were spoken by parents of different socioeconomic levels to their toddlers. The middle-class moms were Robin Williams chatterboxes. Extrapolating their observations over a putative four-year preschool window, they calculated that the middle-class kids heard 45 million words. Poor children, by contrast, were only exposed to a mere 13 million bon mots. To make matters worse, this difference in words spoken seemed to explain the gap in cognitive achievement by the time the kids reached school age (which is, in turn, the root of most achievement differences played forward). So if you are a Freakonomics reader, you’d probably do your child best to stay at home and read to him or her.

Q. Staying married for the kids vs. getting divorced: which is the lesser of two evils? –SC

A. There is so much cultural heat surrounding the issue of divorce that even academic studies can get a bit tricky. There are hundreds, if not thousands, of studies showing that kids from divorced families do worse on scores of outcomes. The problem with all of those research papers is that we can never know the counterfactual: What if those particular parents who divorced had actually stayed together? This would be an entirely different sample of folks from the parents who did in fact stay together—harkening back to Tolstoy’s famous dictum. No, we must confine our inquiry to the ones who did divorce in our sliver of the quantum universe. Would their kids really be better off if they had stayed together in some other quantum state—fighting and yelling and tiptoeing around?

The best study I know of that deals with this apples/oranges issue was by the cool hand of Jonathan Gruber, an MIT economist who examined changing divorce laws across the United States. He found that when states made divorce easier by instituting no-fault, just as New York did in the midst of my own marital split, divorce rates did in fact increase. More importantly, he showed that these kids—whose parents would have stayed together if divorce had still been more difficult—were worse off forty years later in terms of their educational attainment, their earnings, and the fate of their own marriages. Since he estimated these effects based on changes at the state level that had nothing to do with the characteristics of particular happy or unhappy couples, his study was the next best thing to a double-blind medical study that randomly dispensed divorce pills and placebos.

In fact, the way that divorce tended to disadvantage offspring(s) in Gruber’s study jibed with my own more qualitative research: In a 2003 book The Pecking Order, I deployed the term “Cinderella Effect” to argue that divorce didn’t have a universally good, neutral, or bad effect on offspring, but rather, its impact depended on the unique circumstances of the child. Namely, I found that the eldest female child was the most disadvantaged kid in the aftermath of a divorce because of the added, adult roles she tended to take on. While having to care for younger siblings in light of an absent parent and serving as the substitute partner of sorts to the remaining parent may be a maturing experience, it more often resulted in a child becoming resentful about having to grow up too fast and sacrifice his or her childhood autonomy for the sake of younger siblings and the family in general. Often these kids tried to escape the burdens of their family quickly—the same way Cinderella did—through marriage to Prince Charming. Indeed, Gruber found that the effect of divorce on lowering offspring education and earning levels, and raising their divorce rates worked through those offsprings’ own marital history. They tended to marry earlier than they would have had their parents stayed together. Earlier marriages tend to pull individuals away from additional education they might have otherwise pursued. That, in turn, depresses earnings in the long run. What’s more, as we all know, marrying younger means a higher risk of divorce.

Q.Freakonomics has the idea that who you are when you have kids will determine more about your children than what you do as a parent. For example, your children’s happiness, the percentage chance they will graduate from college and the chance they’ll go to jail is much more correlated with who you are as a parent. Do you think that’s true?

I find it to be disturbing, yet also calming. It’s disturbing because parents like to think that all the little things they do will have profound impacts on our children’s happiness and sense of fulfillment. It’s calming because it reduces the anxiety of parenting to some extent.

Where do you fall on the nature vs. nurture scale? If it’s 50/50, it still holds that the best thing you can do for your kids is procreate with someone as far better looking and smarter than you as possible. If it’s 80/20 (or higher), nurture strategies seem like using a bucket rather than a cup to change oceanic levels.

Still, we don’t get to change the nature part after the fact, so give us some nurture tips. –nborlaug

A. In my social science fantasy, my kids are identical twins. At birth, I adopt one of them out to a family in the inner city—where I, myself grew up—and the other to, say, Westport, Connecticut (otherwise known as Northern Hedgistan, thanks to all the hedge fund managers who reside there). Then I stalk them for, oh, thirty-odd years, taking careful notes to know the true effects of social class, net of genetic factors. If I got really into it, I might kidnap and split up other twins in order to test the effects of school resources, childhood nutrition or parenting practices. Oh the possibilities! I could go on, but suffice to say my kids should consider themselves lucky that they are not, in fact, identical twins.

In lieu of kidnapping twins, the way that researchers typically calculated how much a given trait—be that extraversion or earnings—was due to genetics was by comparing how alike identical twins were with respect to how alike (same sex) fraternal twins were. The logic is that the fraternal twins share half their genes on average and the identical twins share all of them, so the degree to which identical twins are more alike than their fraternal counterpart pairs reflects the genetic contribution to that trait.

If two-thirds of our kids’ chances in life were due to their family background, the field of behavioral genetics would have us believe that the vast lion’s share of that predictive power of family of origin was due to genetics. According to these studies, about half of the variation in incomes or job situations was due to our genetic makeup. And only about a sixth resulted from the household environment on which parents could exert some conscious influence. The remaining one-third was a product of random events outside a family’s control: an inspiring teacher, a traumatic accident, or a lucky break at work.

I initially went into the field of genetics to prove these researchers wrong. Genes couldn’t matter that much, I figured. It just didn’t jive with what I saw around me: Siblings seemed so different from each other; I knew plenty of poor kids growing up that I could have imagined achieving great heights had they been reared in better circumstances; and, likewise, in my adulthood I had gotten to know plenty of folks who seemed to be of mediocre talent despite their huge paychecks. Social environment had to count for more. So I decided to go right after the geneticists’ core assumption.

That is, their nifty little calculation relies on one hugely problematic assumption known as the “equal environments assumption.” Put in English, these researchers had to take as a given the notion that identical twins are not treated any more similarly to each other than fraternal twins are (and that identical twins don’t interact with each other more than fraternal twins do in ways that might affect the outcomes in question—i.e. that their mutual, reciprocal influence is no different than that of same gender fraternal twins). Since in my own experience I often couldn’t even tell who was who in an identical twin set, it seemed obvious to me that identical twins were experiencing much more similar environments than fraternal twins were in ways that were not generalizable to us non-twins in the population, and thus the behavioral geneticists were inflating the effects of genes and correspondingly underestimating the impact of family environment.[2]

Determined to prove them wrong and save the day for social scientists, I thought of a trick that would have been unimaginable before the days of 23andme and the like: I would take the fraction of twins who thought they were identical when they were really fraternal (and vice versa) and run the same analysis on them. If they thought they were fraternal twins their whole lives but the laboratory genetic test revealed they were actually identical, we could be sure that they weren’t raised with more similar environments because they had been (mistakenly) socialized as fraternal twins. And ditto in reverse. But when I ran these folks through the statistical models, the results didn’t refute the behavioral geneticists at all. In fact, my models confirmed the high genetic heritability for everything from height to high school GPA to ADHD.

As a social scientist I had to admit defeat. But, I must confess, as a parent it provides me a bit of a relief. On the one hand, if my kids’ chances in life are largely determined by the DNA that their mother and I have passed on, all my math drilling and insistence on reading may have been for little added value. But on the other hand, all the things I did to mess them up probably won’t actually matter all that much in the end either, and I could really relax now that they were both well into the double-digits. After many years of parenting, I am happy to be reduced to what my biology professor called me and all men: A sperm delivery system (and, I’d add, an interactive e-reader of children’s books).

Of course, this doesn’t mean that poverty and other social factors don’t matter. With few exceptions, genes are not deterministic predictors of our outcomes. Most outcomes are the result of what we call G by E—that is, they stem from genetic and environmental factors interacting—don’t give up on teaching your kids math or economics quite yet!

Q. What is the single most important rule of thumb in parenting which you believe will lead one’s child to become a stable, successful and healthy member of society? –Michele

A. Here’s my only rule: Use the scientific method. That is, experiment on your kids. Before you drop a dime on me to child protective services, allow me to explain.

As an immigrant society with no common culture, we Americans have always made things up as we go—be it baseball, jazz or the Internet. Parenting is no different, whether we admit it or not. If we want to keep producing innovative kids who can succeed in today’s global economy, we should be constantly experimenting on them.

For example, I read the latest research on allergies and T-cell response and then intentionally exposed my kids to raw sewage (in small doses, of course) to build up their immune systems. I bribed them to do math thanks to an experiment involving Mexican villagers that demonstrated the effectiveness of monetary incentives for schooling outcomes. I perused a classic study suggesting that confidence-boosting placebos improved kids’ actual cognitive development, fed my kids vitamins before an exam, told them that they were amphetamines—and watched their scores soar.

There’s a method to my madness. Parentology—as I call this approach to raising kids—involves three skills: first, knowing how to read a scientific study; second, experimenting on your kids by deploying that research; and third, involving your kids in the process, both by talking to them about the results and by revising your hypotheses when necessary to adapt the “treatment” to the unique circumstances of your kids. Kids raised this way won’t necessarily end up with 4.0 GPAs, but they will be inquisitive, creative seekers of truth. And hopefully, they won’t call child services on you either.

[1] Flawed because it turns out that the differences may have been over-accentuated due to a heterogeneous white coat effect. That is, the poor families probably clamped up more self-consciously in front of the researchers than did the middle class parents.

[2] Technically, if their genetic similarity in looks is causing the twins to be treated more similarly, then that is an effect of genes and thus should unproblematically be part of the overall “genetic” effect. However, this flies in the face of common sense understandings of what we mean by genetic effects, and makes the estimates less externally valid to the rest of us. However, the increased cross-sibling interaction that may make them turn out more similar is another story—that’s just plain biasing of results.

Adam

I'm interested in hearing more about this 'exposure to raw sewage' bit... more details please!

NZ in Flyover Country

March 26, 2014 @ 8:49pm

"An immigrant society with no common culture"??

I get that this guy's a sociologist and not a historian, but even a quick glance outside the window (provided you don't live in, say, Flushing, NY) shows pretty decisively that while we let in tons of immigrants relative to other countries, we Americans do have our own distinct national identity and culture. And though it's changed in certain ways, we've had one for a long time, too.

Gary Lawrence Murphy

March 27, 2014 @ 12:12am

I like that last rule. Someone once told me, "Children are god's gift of a chemistry set to the parents."

Shane L

March 27, 2014 @ 4:52pm

Regarding divorce one might try looking at other countries. Divorce was illegal in Ireland until 1995 and in Malta until I believe 2011.

Stephany

September 23, 2014 @ 9:04pm

I live in Canada and we do not have universal preschool. What are you talking about?